I was offered a large acrylic tank for sale today while meeting someone who was clearing out his goldfish and koi ponds. But I noticed a 3-inch crack on the far back corner the owner had "repaired." He assured me it's fine, holds water, and won't leak... of course. I'm not convinced. This would be one to avoid at all costs, right? As I remember, patched up acrylic means the tank is pretty much trashed.